Solution:
Image loading and crunching can be heavy on the system.
First of all – the NOTICES you have posted are exxactly that – NOTICES, not errors. (I am talking about the “Notice: unregister_widget_control is deprecated since version 2.8! Use.” type notices)
Tutning wp_debug off will make them go away.
Second – Like said, image handeling is quite heavey on memory. You can try to increase the memory usage to allocate for PHP like so :
// in wp-config.php
define('WP_MEMORY_LIMIT', '64M');//Increase PHP Memory to 64MB
define('WP_MEMORY_LIMIT', '96M'); //Increase PHP Memory to 96MB
(Note : It might not work because of your host settings, but in 95% of the cases, it does)
If that does not help – try to upload the images one by one or two by two and see what happens . you must understand that 2mb images are quite big , and uploading 12 of them together is no joke in terms of memory usage .
It also depends on your custom-size functions (do they require cropping for example ??)
Another last thing you can try is simply not crunching the images (this is highly not recommended – because it will result in serving very heavy images to users – and eat a lot of bandwidth)